Since a liquid crystal itself is a non-self-luminous material in an LCD-TV, the LCD-TV needs a separate light source device called a backlight unit (BLU) on the back surface of a front panel in order to enhance the luminance of a display screen. A line light source emitting from the backlight unit is reflected by a reflecting film, passes through a diffuser, is diffused over the entire surface by a light diffusion film, is converted into a surface light source, and thus illuminates a display screen of a TFT-LCD.
In this case, in order to reduce the processes and further enhance the brightness, methods of enhancing the brightness of a display screen by replacing a light diffusion film have been developed. Representative examples thereof include methods of preparing a film by dispersing a light diffusion particle such as metal oxides in a light emitting layer resin and performing the coating/drying processes.
However, since a metal oxide acts as a photo catalyst under specific conditions in an organic fluorescent film using an organic material, optical characteristics of the organic fluorescent material may be reduced. Therefore, it is difficult to directly apply a metal oxide for light diffusion in a composition or film including an organic fluorescent material.